special sense Flashcards

1
Q

receptor cells make up…

A
  1. Neuroepithelium: retina and olfactory Epithelium, sensory Neurons from neuroectoderm
  2. Sensoepithelium: taste buds and Epithelium in internal ear, Special epithelial cells from Surface ectoderm
  3. Sensory nerve ending (pacinian and Meisners corpuscle)
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2
Q

Ocular refractive media consists of

A

lens, chamber, vitreous humor

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3
Q

Accessory structures

A

eyelids, lacrimal Glands, extraocular muscles, conjunctiva

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4
Q

Developmental Sources of the eye

A
  1. Neural tube: retina, muscle of Iris
  2. Surface ectoderm: lens, anterior Epithelium of Cornea
  3. Head Mesenchyme: all others
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5
Q

Development of eye

A

3rd week:

  • outpockenings –> vesicles attached by optic stalk –> optic Cup –> inner layer (muscle of Iris, neural of retina) and outer layer (Pigment of retina)
  • lense Surface ectoderm –> lens placode –> lens vesicle –>lens
  • optic stalk –> otpic nerve

6th week:
- hyaloid artery into optic Cup –> choroid fissue that Closes befire birth

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6
Q

Wall of the eyeball

A

FIBROUS LAYER

  • Cornea
  • sclera

VASCULAR LAYER

  • Iris
  • ciliary Body
  • choroid

RETIANL LAYER

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7
Q

Cornea

A

avascular!!

  1. Stratified squamous non-keratinized Epithelium
  2. Anterior b.m. (bowman’s membrane)
  3. Stroma of dense collagenous tissue in lamellae
  4. Posterior b.m. (descemet’s membrane)
  5. Pre-Descemet’s membrane (Dua’s layer)
    6- Endothelium
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8
Q

Sclera

A
  • irregular dense collagenous tissue
  • Collagen fibers and elastic fibers
  • blood vessels and nerves

Cornoscleral Limbus: Junction of Cornea and sclera, canal of Schlemm

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9
Q

iris

A
  • highly vascularized
  • non-photosensitive retina on posterior Surface

sphincter pupillae muscle: smooth muscle cells near margin of Iris

dilator pupillae muscle: extends radially, composed of the processes of myoepithelial cells

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10
Q

Ciliary body

A
  • smooth muscles

- inner Surface covered by non-photosensitive retina

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11
Q

Choroid

A
  • pigmented loose CT
  • absorbs light
  • provides support and nutrients for retina
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12
Q

Parts of the retina

A

Photosensitive
Non-photosensitive
- iridial part (behind Iris)
- ciliary part (behind ciliary Body)

ora serrata: line between photosensitive and non-photosensitive retina

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13
Q

Microscopic structure of the retina

A

two layers:

  • outer layer
  • inner layer
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14
Q

Iridial part of the non-photosensitive retina

A

outer layer:
- 1 layer of pigmented myoepithelial cells (dilator pupillae muscle)

inner layer:
1 layer of pigmented cells

  • -> Formation of dilator pupillae
  • -> absorption of light
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15
Q

Ciliary part of non-photosensitive retina

A

outer layer:
1 layer of pigentocyti

inner layer:
1 layer of non-pigmented cuboidal cells

  • ->Secretion of aqueous Humor
  • ->Production of zonular fibers –> suspensory ligament of lens
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16
Q

Photosensitive retina is divided in:

A

outer layer

inner layer

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17
Q

Pigmented (outer) layer of photosensitive retina

A
  • retinal pigement Epithelium (single layer of Pigemtocyti)
  • Basement membrane

pigentocyti have microvilli on inner sruface that go between photoreceptors

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18
Q

Functions of retinal pigemtn epithelium

A
  • absorbs light
  • structural support
  • metabolic support
  • blood- retinal-barrier
  • phagocytoses membranous Disc
  • (re) Synthesis of rhodopsin
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19
Q

(Re) Synthesis of rhodopsin

A

Vitamin A –> Retinol –> retinal

retinal + opsin –> rhodopsin

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20
Q

Neural (inner) layer of photosensitive retina (Groups of Neurons)

A

Photoreceptor cells
Conducting cells
Ganglion cells

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21
Q

Photoreceptor cells are divided in:

A

rod cells

Cone cells

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22
Q

Structure of photoreceptor cells

A

bipolar Neurons

dendrite
Body
axon that Ends in:
- sferule (rod)
- pedicle (cone)
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23
Q

Dendrite of photoreceptor cell

A
  • outer Segment
  • Connecting cilium
  • inner Segment
    >outer part (mitochondria)
    >inner part (Rhodopsin is synthesized)
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24
Q

Outer Segment of rod

A
  • stack of flattened membranous Discs
  • Discs are shed and phagocytosed by RPE
  • light: retinal –> Retinol , release of opsin and changes in permeability of Plasma membranes
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25
Q

Functions of rods

A
  • more sensitive to light

- during period of low light intensity –> Image of gray tones

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26
Q

Outer Segment of cone

A
  • memranous Disc are continuous with Plasma membrane

three classe sof cones
L (Long) M (middle) S (short-wavelength)

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27
Q

Function of cones

A
  • sensitive to red, green and blue regions of visual spectrum
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28
Q

Conducting cells of the retina

A
  • bipolar cells
  • horizontal cells
  • Amacrine cells
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29
Q

Bipolar cells

A

Connections:

  • photoreceptors and Ganglion cells
  • photoreceptors and horizontal cells
  • photoreceptors and amacrine cells
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30
Q

Horizontal cells

A
  • connect rods and cones

- Synapse with bipolar cells

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31
Q

Amacrine cells

A
  • no not have an axon!!!

- connect bipolar and Ganglion cells

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32
Q

Ganglion cells

A
  • large, mulitpolar Neurons
  • with bipolar cells
  • with few amacrine cells
  • axons pass into optic nerve Fiber layer and then to optic nerve
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33
Q

Supporting cells of the retina

A

Müller cells: type of astrocytes

  • apical Ends form outer limiting membrane
  • Basic parts together with b.m. form inner limiting membrane

functions: support, Transfer of metabolites, Regulation of electrolytes

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34
Q

10 histological layers of retina (PPOOOIIGLI)

A

1: Pigmented layer: RPE
2. Photoreceptor layer: outer and inner Segments
3. Outer limiting layer: apical Ends of Mülller cells
4 . Outer nuclear layer: cell bodies of photorecept,
5. Outer plexiform layer: processes of photo, horizontal and bipolar
6. Inner nuclear layer: cell bodies of conducting and Müller
7. Inner plexiform layer: processes of bipolar, amacrine and ganglion
8. Ganglion cell layer: cell bodies of ganglion
9. Layer of optic nerve fibers: axons of glangion cells
10. Inner limiting membrane: Basic Ends of Müller cells

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35
Q

Optic disc

A
  • where fibers of Ganglion cells converge
  • blood vessels pass through Center
  • axons of Ganglion cells are not myelinated except here
36
Q

Macula lutea

A
  • near optic axis of the eyeball
  • there is a Fovea in the middle
  • Fovea is most sensitive area, because
    >lacks bloos vessels
    >contains only cones
    >Monosynaptic Connections between the neurons
37
Q

Monosynaptic connections

A
  • Ratio between cones, bipolar cells, Ganglion cells
    1: 1:1
  • only in macula lutea
38
Q

Inverted eye

A

Photoreceptor dendrites are directed to choroid, not to light

39
Q

Olfactory mucosa layers

A

Olfactory Epithelium

Lamina propdia mucosae

40
Q

Olfactory epithelium

A

Pseudostratified epitheliem with:

  • olfactory cells
  • supporting cells
  • Basal cells
41
Q

Olfactory cell

A
  • bipolar Neurons
  • dendritic processes Project above epitheium and make olfactory knob with cilia
  • Plasma membrane of cilia contains odorant-binding proteins
  • Long axon leaves Epithelium
  • can regenerate
42
Q

Supporting cell in olfactory epithelium

A
  • tall columnar
  • microvilli on apical Surface
    . Metabolic and mechanical support
  • synthesize and secrete odorant binding proteins
43
Q

Lamina propria mucosae in olfactory epithelium

A

loose CT
+ olfactory (Bowman’s) Glands

–> branched tubuloalveolar Glands –> deliver secretions

serour secretion is trap for odoriferous substances

44
Q

Ear is divided into:

A

External ear
Middle ear
Inner ear

conducting structures in all parts
sensory structures in inner ear

45
Q

External ear

A

Pinna: elastic cartilage
External auditory meatus: lined by Skin with hair and wax Glands
Ear drum: Epidermis, middle CT, simple cuboidal pithelium

46
Q

Middle ear

A
eardum to oval windwo
with ossicles (malleus, incus, stapes)
tympanic cavity (simple squamous)
Eustachian tube (pseudostratified)
Mastoid sinuses (simple squamous)
47
Q

Vestibulocochlear apparatus

A
  • in inner ear
  • bony Labyrinth
  • membranous labyrinth
48
Q

Development of the external ear

A
  • Ectoderm (1st pharyngeal groove) –> Epithelium of external auditory meatus
49
Q

Development of the middle ear

A
  • Endodern (1st pharyngeal pouch) –> Epithelium of the cavities of the middle ear
50
Q

Development of inner ear

A
  • ectodermal thickening –> PLACODA OTICA –> FOVEA OTICA –> VESICULAR OTICA
  • Vesicula otica separates from ectoderm and forms sensoepithelium of membranous Labyrinth
  • head Mesenchyme: all CT of the ear
51
Q

The two Labyrinths of inner ear

A

Bony Labyrinth: within temporal bone, filled with perilymph and loose CT

Membranous Labyrinth: filled with endolymph, simple squamous and sensoepithelium

52
Q

Parts of bony labyrinth

A
  • semicircular canals
  • vestibule
  • cochlear canal
53
Q

Parts of membranous labyrinth

A

Semicircular ducts
Utricle and saccule
Cochlear duct

54
Q

Perilymph

A
  • inside bony Labyrinth
  • like ECM
  • high NA, low K
55
Q

Endolymph

A
  • inside membranous Labyrinth
  • like intracellular fluid
  • low Na, high K
  • produced by Stria vascularis
56
Q

Sensory Region of membranous labyrinth

A

3 Cristae ampullares in semicircular ducts
2 maculae in saccule and utricle
1 organ of Corti in cochlear duct

57
Q

Cell types of sensoepithelium

A

Specialized sensory cells (hair cells)

Supporting cells

58
Q

Supporting cells in sensoepithelium

A

on b.m.

support
Nutrition
production of gelatinous material

59
Q

Sensory hair cells in sensoepithelium

A

on supporting cells

Type I (goblet)
Type II (columnar)

Basic part connects with nerve Fiber
Apical part has stereocilia and kinocilia

60
Q

Stereocilia of sensory hair cell

A
  • Long microvilli with actin cores

- immotile

61
Q

Kinocilium of sensory hair cell

A
  • motile

- Arrangement of microtubules

62
Q

Crista ampullaris

A
  • in ampulla of each semicircular canal
  • ducts are lined by simple squamous Epithelium
  • where membranous and bony Labyrinths fuse
  • supporting and hair cells (type I and type II)
  • stereocilia and kinocilia are covered by GELATINUOUS CUPULA
63
Q

How does the crista ampullaris work?

A

sensroy Region of angular acceleration!

  • when head is turned, endolmyph lags behind causing degletcion of gelatuínous cupula
  • ->hyperpolarization or depolarization of hair cell
  • -> excitation or Inhibition
  • ->Excitation of the dendrite
  • -> Impulse to the CNS
64
Q

Macula

A
  • sensoepitheliulm in utricle and saccule
  • utricle and saccule are lined by simple squamous
  • supporting cells
  • hair cells (type I and type II)
65
Q

How does the Macula work?

A
  • Crystals of Calcium Carbonate make otoliths
  • connected by proteins
  • can detect gravity and linear acceleration
  • ->movement of stereocilia and kinocilia
  • ->excitation or Inhibition of hair cell
  • ->Impulse to dendrite and CNS
66
Q

Innervation of vestibular sense organs

A

hair cells are innervated by bipolar sensory Neurons

bodies of Neurons are in vestibular ganglion

67
Q

Cochlea

A
  • cochlear canal around modiolus
  • three spiraling compartments:
    1. Scala vestibuli with perilymph
    2. Scala media with endolymoh
    3- Scala tympani with perilymph

Scala vestibuli makes u turn at helicotrema and travels down to Scala tympani

68
Q

Scala media walls

A

reissner’s membrane
Stria vascularis
Basilar membrane

69
Q

Reissner’s membrane (vestibular membrane)

A
  • between Scala media and Scala vestibuli
  • simple squamous
  • fibrous CT
  • simple squamous
70
Q

Stria vascularis

A
  • pseudostratified

- produces endolymph and regulates ion transport

71
Q

Basilar membrane

A
  • supports organ of Corti

- Collagen fibers and simple squamous

72
Q

Inner Corner of cochlear duct

A

spiral Limbus –> produced tectorial membrane

73
Q

Tectorial membrane

A
  • gelatinous
  • similar to cupula or otolithic membrane
  • covers stereocilia
74
Q

Organ of corti

A

in Scala media

  • sensory hair cells
  • supporting cells

look at drawing!!!!

75
Q

Inner tunnel (tunnel of Corti)

A
  • surrounded by inenr and outer pillar cells
76
Q

Sensory hair cells in organ of corti

A
  • inner hair cells (1 row) –> type I cells
  • Outer hair cells (3-5 rows) –> type II cells
  • stereocilia that insert into tectorial membrane
  • stereocilia are displaced during Vibration
  • don’t have kinocilium!!!!
77
Q

Phalangeal cells

A
  • in organ of Corti (supporting cells)
  • has apical phalangeal process
  • forms reticular plate
  • below reticular plate: corticolymph
  • to stabilize
  • tight junctions to maintain ion gradient
78
Q

Innervation of cochlea

A

hair cells are innervated by bipolar sensory Neurons

Bodies are in spiral ganglion

79
Q

Spiral (cochlear) ganglion

A
  • cell bodies of bipolar Neurons wrap around modiolus

- axons come together as cochlear nerve in Center of modiolus

80
Q

Sound transduction

A
tympanic membrane 
ossicles
oval window
perilymph in Scala vestibuli
round window
sensory hair cells
basilar membrane
81
Q

Taste buds

A

not in filiform papillae
- in stratified non-keratinized Epithelium

also in palate, Pharynx, Epiglottis and other parts of oral mucosa

82
Q

Structure of a taste bud

A

Barrel shaped
Opening at Surface via taste port
contains sensoepithelium

83
Q

Cell types in taste bud

A
  • gustatory cells
  • supporting cells
  • Basal cells
84
Q

Gustatory cells in taste bud

A
  • spindle- shaped

- Long microvilli extendnig into pore

85
Q

Basal cells in taste buds

A
  • near b.m.

- precursors

86
Q

Basic tastes

A
Sweet
Salty
Sour
Bitter
Unami